To compare real-life performance when zoomed-out, I shot this scene with the the Canon ELPH 520 HS / IXUS 500 HS and the Canon ELPH 110 HS / IXUS 125 HS within a few moments of each other using their best quality JPEG settings.

The lenses on both cameras were set to an equivalent field of view and both were set to Program auto exposure mode.

The image above was taken with the Canon ELPH 520 HS / IXUS 500 HS. The lens was set to the maximum 28mm wide angle position and the Canon ELPH 110 HS / IXUS 125 HS with which I've compared it here was zoomed in slightly to give an equivalent vertical field of view. In Program auto mode the camera metered an exposure of 1/1600 at f3.4. The original Superfine JPEG image size was 4.69MB. The crops are taken from the areas marked with red rectangles and presented here at 100%. Image stabilisation was disabled for these tripod-based tests and i-Contrast was left in the default off position on both cameras.

In contrast to the ELPH 110 HS / IXUS 125 HS, the ELPH 520 HS / IXUS 500 HS has picked the widest available aperture for this bright sunny subject. The exposure is good and the histogram extends to both edges of the chart with no clipping. The result is a nicely exposed image with good contrast, accurate white balance, and vibrant natural colours.

Turning to the crops, there's a good level of detail, but some visible noise too. The HS suffix on the ELPH / IXUS range stands for High Sensitivity and highlights the low noise capabilities of their back-illuminated CMOS sensors, but even outdoors in bright light they're not completely noise-free and if you look closely you can see that the areas of flat colour have a noticeable texture to them.

The first crop actually shows a good deal of detail in the chapel and grassy foreground, but take a good look at the horizon line on the left of the crop where the sea meets the sky and it's quite clumpy. If you look closely at the chapel it's clear that the noise in this crop is obscuring the finer detail in the stonework.

The lighthouse is a clear and distinct column with well defined edges and the foreground roofs and window frames also showing a good level of detail. But again, there's visible clumping of the pixels with the sea and the background cliffs looking (in)distinctly impressionistic.

The lens softness in the third crop from the frame edge is taking the edge off the noisiness, but the edges are still not as clean and sharp as they could be. Finally in the fourth crop from the centre of the frame edge detail is reasonably crisp, but there's still that clumpiness texturing flat colour areas. Overall I think it's fair to say that these results are slightly marred by the persistent presence of low ISO noise.

The crops from the ELPH 520 HS / IXUS 500 HS make for an interesting comparison with those from the ELPH 110 HS / IXUS 125 HS. You might think that with a 10 Megapixel sensor the ELPH 520 HS / IXUS 500 HS stands a good chance of producing better results than the 16.1 Megapixel ELPH 110 HS / IXUS 125 HS, but in fact the sensor in the ELPH 520 HS / IXUS 500 HS has a total pixel count of 16.8 Megapixels and is in all likelihood the same sensor as in the ELPH 110 HS / IXUS 125 HS. Only the central portion of the sensor is used, giving an effective count of 10.1 Megapixels.

What does this mean in practice? Well, the results speak for themselves. The ELPH 520 HS / IXUS 500 HS suffers from visible noise at the base 100 ISO sensitivity. The crops from the ELPH 110 HS / IXUS 125 HS are actually very similar, but because (more or less) the full sensor area is used, image detail is larger and less prone to the effects of noise. Side-by-side at screen resolutions you can't really see the difference, but these 100 percent crops tell a different story. Unless you plan to make big prints this may not be a big concern for you, but it's worth knowing that 12x zoom of the ELPH 520 HS / IXUS 500 HS comes at the cost of smaller, noisier images than other ELPH / IXUS models like the ELPH 110 HS / IXUS 125 HS that use the full sensor area.